244 lines
7.8 KiB
C
244 lines
7.8 KiB
C
/*
|
|
* copyright (c) 2005-2012 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* @addtogroup lavu_math
|
|
* Mathematical utilities for working with timestamp and time base.
|
|
*/
|
|
|
|
#ifndef AVUTIL_MATHEMATICS_H
|
|
#define AVUTIL_MATHEMATICS_H
|
|
|
|
#include <stdint.h>
|
|
#include <math.h>
|
|
#include "attributes.h"
|
|
#include "rational.h"
|
|
#include "intfloat.h"
|
|
|
|
#ifndef M_E
|
|
#define M_E 2.7182818284590452354 /* e */
|
|
#endif
|
|
#ifndef M_LN2
|
|
#define M_LN2 0.69314718055994530942 /* log_e 2 */
|
|
#endif
|
|
#ifndef M_LN10
|
|
#define M_LN10 2.30258509299404568402 /* log_e 10 */
|
|
#endif
|
|
#ifndef M_LOG2_10
|
|
#define M_LOG2_10 3.32192809488736234787 /* log_2 10 */
|
|
#endif
|
|
#ifndef M_PHI
|
|
#define M_PHI 1.61803398874989484820 /* phi / golden ratio */
|
|
#endif
|
|
#ifndef M_PI
|
|
#define M_PI 3.14159265358979323846 /* pi */
|
|
#endif
|
|
#ifndef M_PI_2
|
|
#define M_PI_2 1.57079632679489661923 /* pi/2 */
|
|
#endif
|
|
#ifndef M_SQRT1_2
|
|
#define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
|
|
#endif
|
|
#ifndef M_SQRT2
|
|
#define M_SQRT2 1.41421356237309504880 /* sqrt(2) */
|
|
#endif
|
|
#ifndef NAN
|
|
#define NAN av_int2float(0x7fc00000)
|
|
#endif
|
|
#ifndef INFINITY
|
|
#define INFINITY av_int2float(0x7f800000)
|
|
#endif
|
|
|
|
/**
|
|
* @addtogroup lavu_math
|
|
*
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Rounding methods.
|
|
*/
|
|
enum AVRounding {
|
|
AV_ROUND_ZERO = 0, ///< Round toward zero.
|
|
AV_ROUND_INF = 1, ///< Round away from zero.
|
|
AV_ROUND_DOWN = 2, ///< Round toward -infinity.
|
|
AV_ROUND_UP = 3, ///< Round toward +infinity.
|
|
AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
|
|
/**
|
|
* Flag telling rescaling functions to pass `INT64_MIN`/`MAX` through
|
|
* unchanged, avoiding special cases for #AV_NOPTS_VALUE.
|
|
*
|
|
* Unlike other values of the enumeration AVRounding, this value is a
|
|
* bitmask that must be used in conjunction with another value of the
|
|
* enumeration through a bitwise OR, in order to set behavior for normal
|
|
* cases.
|
|
*
|
|
* @code{.c}
|
|
* av_rescale_rnd(3, 1, 2, AV_ROUND_UP | AV_ROUND_PASS_MINMAX);
|
|
* // Rescaling 3:
|
|
* // Calculating 3 * 1 / 2
|
|
* // 3 / 2 is rounded up to 2
|
|
* // => 2
|
|
*
|
|
* av_rescale_rnd(AV_NOPTS_VALUE, 1, 2, AV_ROUND_UP | AV_ROUND_PASS_MINMAX);
|
|
* // Rescaling AV_NOPTS_VALUE:
|
|
* // AV_NOPTS_VALUE == INT64_MIN
|
|
* // AV_NOPTS_VALUE is passed through
|
|
* // => AV_NOPTS_VALUE
|
|
* @endcode
|
|
*/
|
|
AV_ROUND_PASS_MINMAX = 8192,
|
|
};
|
|
|
|
/**
|
|
* Compute the greatest common divisor of two integer operands.
|
|
*
|
|
* @param a,b Operands
|
|
* @return GCD of a and b up to sign; if a >= 0 and b >= 0, return value is >= 0;
|
|
* if a == 0 and b == 0, returns 0.
|
|
*/
|
|
int64_t av_const av_gcd(int64_t a, int64_t b);
|
|
|
|
/**
|
|
* Rescale a 64-bit integer with rounding to nearest.
|
|
*
|
|
* The operation is mathematically equivalent to `a * b / c`, but writing that
|
|
* directly can overflow.
|
|
*
|
|
* This function is equivalent to av_rescale_rnd() with #AV_ROUND_NEAR_INF.
|
|
*
|
|
* @see av_rescale_rnd(), av_rescale_q(), av_rescale_q_rnd()
|
|
*/
|
|
int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
|
|
|
|
/**
|
|
* Rescale a 64-bit integer with specified rounding.
|
|
*
|
|
* The operation is mathematically equivalent to `a * b / c`, but writing that
|
|
* directly can overflow, and does not support different rounding methods.
|
|
* If the result is not representable then INT64_MIN is returned.
|
|
*
|
|
* @see av_rescale(), av_rescale_q(), av_rescale_q_rnd()
|
|
*/
|
|
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd) av_const;
|
|
|
|
/**
|
|
* Rescale a 64-bit integer by 2 rational numbers.
|
|
*
|
|
* The operation is mathematically equivalent to `a * bq / cq`.
|
|
*
|
|
* This function is equivalent to av_rescale_q_rnd() with #AV_ROUND_NEAR_INF.
|
|
*
|
|
* @see av_rescale(), av_rescale_rnd(), av_rescale_q_rnd()
|
|
*/
|
|
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
|
|
|
|
/**
|
|
* Rescale a 64-bit integer by 2 rational numbers with specified rounding.
|
|
*
|
|
* The operation is mathematically equivalent to `a * bq / cq`.
|
|
*
|
|
* @see av_rescale(), av_rescale_rnd(), av_rescale_q()
|
|
*/
|
|
int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
|
|
enum AVRounding rnd) av_const;
|
|
|
|
/**
|
|
* Compare two timestamps each in its own time base.
|
|
*
|
|
* @return One of the following values:
|
|
* - -1 if `ts_a` is before `ts_b`
|
|
* - 1 if `ts_a` is after `ts_b`
|
|
* - 0 if they represent the same position
|
|
*
|
|
* @warning
|
|
* The result of the function is undefined if one of the timestamps is outside
|
|
* the `int64_t` range when represented in the other's timebase.
|
|
*/
|
|
int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
|
|
|
|
/**
|
|
* Compare the remainders of two integer operands divided by a common divisor.
|
|
*
|
|
* In other words, compare the least significant `log2(mod)` bits of integers
|
|
* `a` and `b`.
|
|
*
|
|
* @code{.c}
|
|
* av_compare_mod(0x11, 0x02, 0x10) < 0 // since 0x11 % 0x10 (0x1) < 0x02 % 0x10 (0x2)
|
|
* av_compare_mod(0x11, 0x02, 0x20) > 0 // since 0x11 % 0x20 (0x11) > 0x02 % 0x20 (0x02)
|
|
* @endcode
|
|
*
|
|
* @param a,b Operands
|
|
* @param mod Divisor; must be a power of 2
|
|
* @return
|
|
* - a negative value if `a % mod < b % mod`
|
|
* - a positive value if `a % mod > b % mod`
|
|
* - zero if `a % mod == b % mod`
|
|
*/
|
|
int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
|
|
|
|
/**
|
|
* Rescale a timestamp while preserving known durations.
|
|
*
|
|
* This function is designed to be called per audio packet to scale the input
|
|
* timestamp to a different time base. Compared to a simple av_rescale_q()
|
|
* call, this function is robust against possible inconsistent frame durations.
|
|
*
|
|
* The `last` parameter is a state variable that must be preserved for all
|
|
* subsequent calls for the same stream. For the first call, `*last` should be
|
|
* initialized to #AV_NOPTS_VALUE.
|
|
*
|
|
* @param[in] in_tb Input time base
|
|
* @param[in] in_ts Input timestamp
|
|
* @param[in] fs_tb Duration time base; typically this is finer-grained
|
|
* (greater) than `in_tb` and `out_tb`
|
|
* @param[in] duration Duration till the next call to this function (i.e.
|
|
* duration of the current packet/frame)
|
|
* @param[in,out] last Pointer to a timestamp expressed in terms of
|
|
* `fs_tb`, acting as a state variable
|
|
* @param[in] out_tb Output timebase
|
|
* @return Timestamp expressed in terms of `out_tb`
|
|
*
|
|
* @note In the context of this function, "duration" is in term of samples, not
|
|
* seconds.
|
|
*/
|
|
int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t *last, AVRational out_tb);
|
|
|
|
/**
|
|
* Add a value to a timestamp.
|
|
*
|
|
* This function guarantees that when the same value is repeatly added that
|
|
* no accumulation of rounding errors occurs.
|
|
*
|
|
* @param[in] ts Input timestamp
|
|
* @param[in] ts_tb Input timestamp time base
|
|
* @param[in] inc Value to be added
|
|
* @param[in] inc_tb Time base of `inc`
|
|
*/
|
|
int64_t av_add_stable(AVRational ts_tb, int64_t ts, AVRational inc_tb, int64_t inc);
|
|
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
#endif /* AVUTIL_MATHEMATICS_H */
|